School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
MR Research Collaborations, Siemens Healthcare Limited, Newton House, Sir William Siemens Square, Frimley, Camberley, Surrey, UK.
Magn Reson Med. 2023 Jun;89(6):2242-2254. doi: 10.1002/mrm.29613. Epub 2023 Feb 10.
To develop a motion-robust reconstruction technique for free-breathing cine imaging with multiple averages.
Retrospective motion correction through multiple average k-space data elimination (REMAKE) was developed using iterative removal of k-space segments (from individual k-space samples) that contribute most to motion corruption while combining any remaining segments across multiple signal averages. A variant of REMAKE, termed REMAKE+, was developed to address any losses in SNR due to k-space information removal. With REMAKE+, multiple reconstructions using different initial conditions were performed, co-registered, and averaged. Both techniques were validated against clinical "standard" signal averaging reconstruction in a static phantom (with simulated motion) and 15 patients undergoing free-breathing cine imaging with multiple averages. Quantitative analysis of myocardial sharpness, blood/myocardial SNR, myocardial-blood contrast-to-noise ratio (CNR), as well as subjective assessment of image quality and rate of diagnostic quality images were performed.
In phantom, motion artifacts using "standard" (RMS error [RMSE]: 2.2 ± 0.5) were substantially reduced using REMAKE/REMAKE+ (RMSE: 1.5 ± 0.4/1.0 ± 0.4, p < 0.01). In patients, REMAKE/REMAKE+ led to higher myocardial sharpness (0.79 ± 0.09/0.79 ± 0.1 vs. 0.74 ± 0.12 for "standard", p = 0.004/0.04), higher image quality (1.8 ± 0.2/1.9 ± 0.2 vs. 1.6 ± 0.4 for "standard", p = 0.02/0.008), and a higher rate of diagnostic quality images (99%/100% vs. 94% for "standard"). Blood/myocardial SNR for "standard" (94 ± 30/33 ± 10) was higher vs. REMAKE (80 ± 25/28 ± 8, p = 0.002/0.005) and tended to be lower vs. REMAKE+ (105 ± 33/36 ± 12, p = 0.02/0.06). Myocardial-blood CNR for "standard" (61 ± 22) was higher vs. REMAKE (53 ± 19, p = 0.003) and lower vs. REMAKE+ (69 ± 24, p = 0.007).
Compared to "standard" signal averaging reconstruction, REMAKE and REMAKE+ provide improved myocardial sharpness, image quality, and rate of diagnostic quality images.
开发一种用于多平均自由呼吸电影成像的运动鲁棒重建技术。
通过迭代去除对运动伪影贡献最大的多个平均 k 空间数据（从单个 k 空间样本中去除）来进行回顾性运动校正（REMAKE），同时组合多个信号平均中任何剩余的片段。开发了 REMAKE 的一种变体，称为 REMAKE+，以解决由于 k 空间信息去除而导致的任何 SNR 损失。使用不同的初始条件进行多次重建，进行配准和平均。这两种技术都在静态体模（模拟运动）和 15 名接受多平均自由呼吸电影成像的患者中与临床“标准”信号平均重建进行了验证。对心肌锐利度、血液/心肌 SNR、心肌-血液对比度噪声比（CNR）进行定量分析，并对图像质量和诊断质量图像的比率进行主观评估。
在体模中，使用“标准”（均方根误差 [RMSE]：2.2±0.5）的运动伪影显著减少，使用 REMAKE/REMAKE+（RMSE：1.5±0.4/1.0±0.4，p<0.01）。在患者中，REMAKE/REMAKE+导致更高的心肌锐利度（0.79±0.09/0.79±0.1 与“标准”相比为 0.74±0.12，p=0.004/0.04）、更高的图像质量（1.8±0.2/1.9±0.2 与“标准”相比为 1.6±0.4，p=0.02/0.008）和更高的诊断质量图像比率（99%/100%与“标准”的 94%）。“标准”的血液/心肌 SNR（94±30/33±10）高于 REMAKE（80±25/28±8，p=0.002/0.005），且低于 REMAKE+（105±33/36±12，p=0.02/0.06）。“标准”的心肌-血液 CNR（61±22）高于 REMAKE（53±19，p=0.003），低于 REMAKE+（69±24，p=0.007）。
与“标准”信号平均重建相比，REMAKE 和 REMAKE+提供了更高的心肌锐利度、图像质量和诊断质量图像的比率。
